Re: [boost] dynamic_bitset request

From: David Abrahams (dave_at_[hidden])
Date: 2002-07-29 10:58:05

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           David Abrahams * Boost Consulting
dave_at_[hidden] * http://www.boost-consulting.com

----- Original Message -----
From: "Jeremy Siek" <jsiek_at_[hidden]>
To: "boost" <boost_at_[hidden]>
Sent: Monday, July 29, 2002 11:37 AM
Subject: Re: [boost] dynamic_bitset request

> Hi Dave,
>
> On Sat, 27 Jul 2002, David Abrahams wrote:
> dave> How about operator-() for set difference? That seems like an
obvious
> dave> need...
>
> One small problem with this is that one metaphor for dynamic_bitset is
> that of a big integer. All the current operators are borrowed from the
> builtin operators on an unsigned int. The problem is that operator-
> doesn't mean set difference for unsigned int, but subtraction.

Yeah, I understand, but dynamic_bitset doesn't really come close to
modeling a numeric type. I don't think crippling its usefulness as a set
(OK I'm being extreme here) is worth it.

In fact, it's really the other way around: the existence of bitwise
operators means that the built-in integers sort-of model sets in a
half-arsed way.

Someone should implement dynamic_bigint. Until then, dynamic_bitset should
be a great set rather than a wimpy one ;-)